Search results

wat

Omg idk any synthetic condensation polymers :'( Is this even part of syllabus. We should do 6/7 mark Q's from past papers and analyse where the marks go or critique responses

Measuring the voltage between two metals doesn't involve H2 gas though... that's why I deducted a mark. What you're thinking of is calculating the electric potential of metals RELATIVE to H2 gas (which forms the electric potential table)

This is good :) But maybe I would have put 2 + 3 together i.e. Standard conditions were not used (25 deg C, 100kPa pressure). And then put a third point (like the impurities as mentioned by harrypotterfan)

AH you are right. Sorry guys. I was thinking of standard conditions for the BOD test (its 20deg not 25deg) 25 deg, 100 kPa

Some criticism - You're using a hydrogen electrode? Isn't the question asking for voltage between two metals X and Y? - 2 is similar to 1 (you could also argue the alternative; too high concentration) Edit: Also your conditions for standard galvanic cell is wrong

Do you really think its nice? idk man that's like a 1/3 to me

Hahaha fixing an acid spill with a base spill :D

Depends how they word it. Are they asking you for the molar heat of combustion or change in enthalpy? If neither, then be safe and just say "molar heat of combustion: {some positive value}" or alternatively "delta H = {some positive/negative value accordingly}"

Heat of combustion is always a positive value

rofl mate

Discussion is always good :) I wouldn't discount measuring DO/BOD entirely. I think it is often a "good" but not best measurement of eutrophication which is why you may see it as the answer in MCQ for measuring eutrophication. But in long responses, go with colourimetric analysis for reasons...

BOLD: Yes I've been saying that considering other factors, then measurement of DO/BOD is not valid for purposes of monitoring eutrophication (which is the Q). Correct me if I'm wrong, but your method (measuring significant low DO and high BOD) only indicates algal blooms. How is that...

Organic wastes from sewerage, agricultural run off, etc. also cause low DO and high BOD. Also, photosynthesis from aquatic plants affects DO. Example scenario: TDS and turbidity of waterway is affected such that photosynthesis activity of aquatic plants is reduced. This leads to a decrease in...

I don't think DO/BOD is a valid measurement of eutrophication because it is affected by too many variables other than phosphorous/nitrogen content i.e. algae activity. Do you have a source?? I havn't been doing any chem lately so I might be wrong :X

Faraday - Induction of emf Lenz - Effect/nature of the induced emf

So does combustion result in liquid or gaseous water as one of the products? I've seen both in MANY sources and it has confused me all my life lol

1) Just memorise that it's used as an additive in concrete to de-ice roads 2) Oh crap... I read it wrong. Yes youre right it does increase TDS SORRY. I guess you could talk about increased salinity for it (I'll need to google the effects of this and add it to my notes). Thanks :D Learnt...

You just needed to elaborate on what the free radicals do :) Your logic in that solution was: formation of free radicals --> boom ozone depletion. Instead it should be more like: formation of free radicals --> reaction with existing ozone --> destroy and cause ozone depletion. Just walk through...

Critique so you can improve @emilios: "While there is some market for the calcium chloride byproduct, the supply exceeds the demand" Providing an example of the "demand" is good if this Q worth >=4 marks "significantly increase the level of TDS" NOPE...... (increased pH & hardening of water)...